Defensive publication



ft (9 DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Apr. 11, 1968, 849 O.G. 1221. Identification is by serial number of the application and the heading indicates the number of pages of specification, including claims, and of sheets of drawing contained in the application as originally filed. The file of this application is available to the public for inspection; reproduction may be purchased for '30 cents per sheet.

Applications published under the Defensive Publication Program have not been examined as to the merits of alleged invention. The Patent Ofiice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED APRIL 15, 1969 707 405 PREPARATION OF PHTl'iIALIC ACIDS BY SLOW OXIDATION Frederic B. Kirby, 13 Council Trail, Indian Field, Del. 19703 Filed Feb. 23, 1968. Published Apr. 15, 1969 Class 260-524 No Drawing. 13 Pages Specification High purity phthalic acids such as terephthalic acid are prepared from methyl-substituted benzenes such as p-xylene in solution in aliphatic monocarboxylic acid (e.g., acetic acid) in the presence of cobalt-containing catalyst (e.g., cobalt acetate tetrahydrate) and Without the aid of a promoter, by contacting the reaction mixture, under essentially atmospheric pressure, *with substantially pure molecular oxygen for a period of at least days and preferably at least about 6.5 days, while agitating the reaction mixture and maintaining its temperature at about from to 105 C., and preferably at least C. The resulting phthalic acid is collected, e.g., by filtration, washed with aliphatic acid solvent (e.g., acetic acid), and then dried to give (based on the Weight of initial methylswbstituted benzene) at least a 94% yield of phthalic acid (calculated as acid) which acid has a purity of at least about 97% by weight. 

